Methods and apparatus for engaging a valve prosthesis with tissue

ABSTRACT

A prosthetic valve comprises a self-expanding frame which includes a self-expanding atrial skirt that forms a flanged region, a self-expanding ventricular skirt, and a first self-expanding tab coupled with the ventricular skirt. A receptacle for receiving a valve leaflet is formed by the area bounded by an outer surface of the atrial skirt, an outer surface of the ventricular skirt, and an inner surface of the first tab. The receptacle has a window for receiving the valve leaflet that is defined by a gap between an edge of the flange and a tip of the first tab. The gap is maximized when the tip of the first tab is unconstrained and a base of the first tab is at least partially constrained. The gap is minimized when the tip of the first tab and its base are unconstrained.

CROSS-REFERENCE

The present application is a non-provisional of, and claims the benefitof U.S. Provisional Patent Application No. 61/598,626 filed Feb. 14,2012; the entire contents of which are incorporated herein by reference.

The present application is related to U.S. patent application Ser. No.13/096,572 filed Apr. 28, 2011; and U.S. patent application Ser. No.13/679,920 filed Nov. 16, 2012; the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to medical devices and methods,and more particularly relates to the treatment of valve insufficiency,such as mitral insufficiency, also referred to as mitral regurgitation.The use of prosthetic valves delivered by traditional surgicalimplantation methods, or by less invasive percutaneous catheter orminimally invasive transapical methods are one possible treatment forvalvar insufficiency (also referred to as regurgitation).

The heart of vertebrate animals is divided into four chambers, and isequipped with four valves (the mitral, aortic, pulmonary and tricuspidvalves) that ensure that blood pumped by the heart flows in a forwarddirection through the cardiovascular system. The mitral valve of ahealthy heart prevents the backflow of blood from the left ventricleinto the left atrium of the heart, and comprises two flexible leaflets(anterior and posterior) that close when the left ventricle contracts.The leaflets are attached to a fibrous annulus, and their free edges aretethered by subvalvular chordae tendineae to papillary muscles in theleft ventricle to prevent them from prolapsing into the left atriumduring the contraction of the left ventricle.

Various cardiac diseases or degenerative changes may cause dysfunctionin any of these portions of the mitral valve apparatus, causing themitral valve to become abnormally narrowed or dilated, or to allow bloodto leak (i.e. regurgitate) from the left ventricle back into the leftatrium. Any such impairments compromise cardiac sufficiency, and can bedebilitating or life threatening.

Numerous surgical methods and devices have accordingly been developed totreat mitral valve dysfunction, including open-heart surgical techniquesfor replacing, repairing or re-shaping the native mitral valveapparatus, and the surgical implantation of various prosthetic devicessuch as annuloplasty rings to modify the anatomy of the native mitralvalve. More recently, less invasive transcatheter techniques for thedelivery of replacement mitral valve assemblies have been developed. Insuch techniques, a prosthetic valve is generally mounted in a crimpedstate on the end of a flexible catheter and advanced through a bloodvessel or the body of the patient until the valve reaches theimplantation site. The prosthetic valve is then expanded to itsfunctional size at the site of the defective native valve.

While these devices and methods are promising treatments for valvarinsufficiency, they can be difficult to deliver, expensive tomanufacture, or may not be indicated for all patients. Additionally,these devices are often anchored into the native valve often by engagingtissue such as the native valve leaflets. Capturing a moving valveleaflet can be challenging. Therefore, it would be desirable to provideimproved devices and methods for the treatment of valvar insufficiencysuch as mitral insufficiency. It would be desirable if these devicescould easily engage tissue and anchor the device at the treatment site.At least some of these objectives will be met by the devices and methodsdisclosed below.

2. Description of the Background Art

By way of example, PCT international patent number PCT/US2008/0544 0(published as PCT international publication no. WO2008/103722), thedisclosure of which is hereby incorporated by reference, describes atranscatheter mitral valve prosthesis that comprises a resilient ring, aplurality of leaflet membranes mounted with respect to the ring so as topermit blood flow therethrough in one direction, and a plurality oftissue-engaging positioning elements movably mounted with respect to thering and dimensioned to grip the anatomical structure of the heart valveannulus, heart valve leaflets, and/or heart wall. Each of thepositioning elements defines respective proximal, intermediate, anddistal tissue engaging regions cooperatively configured and dimensionedto simultaneously engage separate corresponding areas of the tissue ofan anatomical structure, and may include respective first, second, andthird elongate tissue-piercing elements. The valve prosthesis may alsoinclude a skirt mounted with respect to the resilient ring for sealing aperiphery of the valve prosthesis against a reverse flow of blood aroundthe valve prosthesis.

PCT international patent number PCT/US2009/041754 (published as PCTinternational publication no. WO2009/134701), the disclosure of which ishereby incorporated by reference, describes a prosthetic mitral valveassembly that comprises an anchor or outer support frame with a flaredupper end and a tapered portion to fit the contours of the native mitralvalve, and a tissue-based one-way valve mounted therein. The assembly isadapted to expand radially outwardly and into contact with the nativeheart tissue to create a pressure fit, and further includes tensionmembers anchoring the leaflets of the valve assembly to a suitablelocation on the heart to function as prosthetic chordae tendineae.

Also known are prosthetic mitral valve assemblies that utilize a clawstructure for attachment of the prosthesis to the heart (see, forexample, U.S. patent application publication no. US2007/0016286 toHermann et al., the disclosure of which is hereby incorporated byreference), as are prosthetic mitral valve assemblies that rely on theapplication of axial rather than radial clamping forces to facilitatethe self-positioning and self-anchoring of the prosthesis with respectto the native anatomical structure.

Another method which has been proposed as a treatment of mitral valveregurgitation is the surgical bow tie method, which recently has beenadapted into a minimally invasive catheter based treatment where animplant is used to clip the valve leaflets together. This procedure ismore fully disclosed in the scientific and patent literature, such as inU.S. Pat. No. 6,629,534 to St. Goar et al., the entire contents of whichare incorporated herein by reference.

Other relevant publications include U.S. Patent Publication No.2011/0015731 to Carpentier et al. and WO 2011137531 to Lane et al. Whilesome of these devices and methods are promising, there still is a needfor improved devices and methods that will further allow more accuratepositioning of a prosthetic valve and that will also more securelyanchor the valve in place. At least some of these objectives will be metby the exemplary embodiments disclosed herein.

SUMMARY OF THE INVENTION

The present invention generally relates to medical devices and methods,and more particularly prosthetic valves used to treat mitralregurgitation. While the present disclosure focuses on the use of aprosthetic valve for treating mitral regurgitation, this is not intendedto be limiting. The prosthetic valves disclosed herein may also be usedto treat other body valves including other heart valves or venousvalves. Exemplary heart valves include the aortic valve, the tricuspidvalve, or the pulmonary valve. One of skill in the art will alsoappreciate that other body valves may also be treated with the devicesand methods disclosed herein

In a first aspect of the present invention, a prosthetic valve comprisesa self-expanding frame having a superior end, an inferior end, and amidsection therebetween. The frame has an expanded configuration and acollapsed configuration. The collapsed configuration is adapted to bedelivered to a patient's heart, and the expanded configuration isadapted to anchor the self-expanding frame in the patient's heart. Theframe comprises a self-expanding atrial skirt adjacent the superior end,a self-expanding ventricular skirt adjacent the inferior end and firstself-expanding tab adjacent the inferior end and coupled with theventricular skirt. The atrial skirt forms a flanged region afterself-expansion and that is configured to anchor the self-expanding frameto an atrial surface of the heart. The flanged region also comprises anedge of the flange. The ventricular skirt anchors the self-expandingframe to a ventricular surface of the heart after self-expansion. Thefirst tab is coupled with the ventricular skirt and has a tip. The firsttab radially self-expands when a constraint is removed therefrom. Areceptacle is formed by the area bounded by the outer surface of theatrial skirt, and the outer surface of the ventricular skirt, and theinner surface of the first tab. The receptacle is adapted to receive avalve leaflet. A window in the receptacle is adapted to receive thevalve leaflet and is defined by the gap between the edge of the flangeand the tip of the first tab. The gap is maximized when the tip of thefirst tab is unconstrained and the base of the first tab is at leastpartially constrained. The gap is minimized when the tip of the firsttab is unconstrained and the base of the first tab is alsounconstrained.

When the gap is maximized, the window may be adapted to receive thevalve leaflet in the receptacle, and when the gap is minimized, thereceptacle may be adapted to engage the valve leaflet and anchor theprosthetic vale thereto. The tip of the first tab may move toward theedge of the flange when the base of the first tab is released from aconstraint. The tip of the tab may be adapted to engage a fibroustrigone or an anterior or posterior mitral valve leaflet. An angle α maybe defined by an inner surface of the first tab and an outer surface ofthe ventricular skirt. Angle α may become more acute when the base ofthe first tab is released from a constraint and the tip of the first tabis also unconstrained. Angle α may be maximized when the tip of thefirst tab is unconstrained and the base of the first tab is at leastpartially constrained.

The prosthesis may further comprise a commissure post coupled with theself-expanding frame and that has an end extending radially inward. Anangle β may be defined by an outer surface of the commissure post and aninner surface of the ventricular skirt. Angle β may be minimized whenthe base of the first tab is at least partially constrained and the tipof the first tab is unconstrained. Angle β may be maximized when thebase of the first tab is unconstrained and the tip of the first tab isunconstrained. The commissure post may be adapted to remain coupled to adelivery catheter after the base of the first tab and the tip of thefirst tab are unconstrained. A cover may be disposed at least partiallyover the self-expanding frame, and the cover may facilitate tissueingrowth. The cover may comprise fabric, tissue or a polymer.

In some embodiments, the atrial skirt may expand before the tab and thusthe atrial skirt may anchor the prosthetic cardiac valve to the atriumbefore the tab anchors the prosthetic cardiac valve to the valveleaflet. The tab may expand to a position transverse to a longitudinalaxis of the prosthetic cardiac valve followed by expansion to a positionmore vertically oriented and that may be more parallel or substantiallyparallel to the longitudinal axis of the prosthetic cardiac valve.

In another aspect of the present invention, a method for anchoring aprosthetic valve to a cardiac valve having a valve leaflet comprisesproviding a delivery system having an outer sheath, and providing aprosthetic valve. The prosthetic valve is carried by the deliverysystem, and the prosthetic valve comprises an atrial skirt, aventricular skirt and a first tab coupled to the ventricular skirt. Anouter surface of the atrial skirt, an outer surface of the ventricularskirt, and an inner surface of the first tab forms a leaflet receptacle.The leaflet receptacle has a window for receiving the valve leaflet. Thewindow is defined by a gap between an edge of the atrial skirt and a tipof the first tab. The method also comprises positioning the prostheticvalve adjacent the cardiac valve, self-expanding the atrial skirt intoengagement with an atrial surface of the cardiac valve, andself-expanding the ventricular skirt into engagement with a ventricularsurface of the cardiac valve. A constraint is removed from a portion ofthe first tab thereby allowing a tip of the first tab to expand radiallyoutward. The valve leaflet is received through the window and into theleaflet receptacle, and partial or total closure of the window engagesthe valve leaflet with the leaflet receptacle thereby anchoring theprosthetic valve to the valve leaflet.

Positioning the prosthetic valve adjacent the cardiac valve may comprisetransseptal or transapical delivery of the prosthetic valve to thecardiac valve. Self-expanding the atrial skirt may comprise retractingthe outer sheath thereby removing a constraint therefrom. Self-expandingthe atrial skirt may comprise forming a flange which engages an atrialsurface of the cardiac valve thereby anchoring the prosthetic valvethereagainst. Self-expanding the ventricular skirt may compriseretracting the outer sheath thereby removing a constraint therefrom.Self-expanding the ventricular skirt may also comprise expanding theventricular skirt into engagement with a ventricular surface of thecardiac valve thereby anchoring the prosthetic valve thereagainst.Removing a constraint from a portion of the first tab may compriseretracting the outer sheath therefrom. At least partially closing thewindow may comprise further retracting the outer sheath to remove aconstraint from a base of the first tab thereby allowing the base toradially expand outward such that the tip of the first tab moves towardthe edge of the atrial skirt. The valve leaflet may comprise an anteriormitral valve leaflet and the method may further comprise engaging thetip of the first tab with a fibrous trigone of the mitral valve. Theprosthetic valve may also have a second anterior tab that also has a tipwhich engages an opposite side of the fibrious trigone. The valveleaflet may comprise a posterior mitral valve leaflet, and engaging thevalve leaflet may comprise engaging the posterior mitral valve leaflet.

In yet another aspect of the present invention, a system for deploying aprosthetic valve comprises a prosthetic cardiac valve comprising anatrial skirt, a ventricular skirt, and a tab coupled to the ventricularskirt. The system also includes a delivery system having an outersheath, and the prosthetic cardiac valve is carried by the deliverysystem. The outer sheath comprises a cam on the outer sheath adjacent adistal end thereof. Partial retraction of the outer sheath releases aconstraint from the atrial skirt and the ventricular skirt therebyallowing self-expansion thereof. Further retraction of the outer sheathreleases a constraint from the tab thereby allowing a tip of the tab toradially self-expand outward forming a window between an edge of theatrial skirt and the tip of the tab. While the cam remains engaged witha base portion of the tab, the tip self-expands such that the windowopens to its maximum size. Further retraction of the outer sheathdisengages the cam from the base portion of the tab thereby releasing aconstraint therefrom. This allows the base of the tab to radially expandoutward and the tip of the tab moves toward the edge of the atrialskirt, at least partially closing the window.

The cam may comprise an annular flange disposed on an inside surface ofthe outer sheath. The outer sheath may comprise a lumen and theprosthetic cardiac valve may be disposed therein. The window may beadapted to receive a valve leaflet while open. The prosthetic valve maybe anchored to the valve leaflet after the window is at least partiallyclosed. The system may further comprise a cover disposed at leastpartially over the prosthetic cardiac valve. The cover may facilitatetissue ingrowth. The cover may comprise fabric, tissue, or a polymer.The tip of the tab may be adapted to engage a fibrous trigone. The tabmay be adapted to engage an anterior or a posterior mitral valveleaflet.

In another aspect of the present invention, a method for anchoring aprosthetic valve to a cardiac valve having a valve leaflet comprisesproviding a prosthetic cardiac valve that comprises an atrial skirt, aventricular skirt, and a tab coupled to the ventricular skirt, and alsoproviding a delivery system with an outer sheath. The outer sheath has acam adjacent a distal end thereof, and wherein the prosthetic cardiacvalve is carried by the delivery system. The method also includesself-expanding the atrial skirt and the ventricular skirt, as well asself-expanding the tab such that a tip of the tab expands radiallyoutward and whereby a window is formed between an edge of the atrialskirt and the tip of the tab. The window is opened to its maximum sizeand a valve leaflet is received in the window. The base portion of thetab is self-expanded radially outward and the window is at leastpartially closed when the tip of the tab moves toward the edge of theatrial skirt.

Self-expanding the atrial skirt and the ventricular skirt may compriseretracting the outer sheath thereby releasing a constraint therefrom.Self-expanding the atrial skirt may allow the atrial skirt toself-expand into engagement with an atrial surface of the cardiac valve.Self-expanding the ventricular skirt may allow the ventricular skirt toself-expand into engagement with a ventricular surface of the cardiacvalve. Self-expanding the tab may comprise retracting the outer sheaththereby releasing a constraint therefrom. Opening the window maycomprise maintaining engagement of the cam with a base portion of thetab such that the tip self-expands independently of the base of the tab.Self-expanding the base portion may comprise disengaging the cam fromthe base portion of the tab thereby releasing a constraint therefrom.The valve leaflet may comprise an anterior mitral valve leaflet, and themethod may further comprise engaging the tip of the tab with a fibroustrigone of the mitral valve. The valve leaflet may comprise a posteriormitral valve leaflet, and the method may further comprise engaging thetab with the posterior mitral valve leaflet.

In still another aspect of the present invention, a system for deployinga prosthetic valve comprises a prosthetic cardiac valve comprising anatrial skirt, a ventricular skirt, and a tab coupled to the ventricularskirt. The system also comprises a delivery system comprising an outersheath and a pusher element. The prosthetic cardiac valve is carried bythe delivery system and the pusher element is slidably disposed underthe outer sheath. Partial retraction of the outer sheath releases aconstraint from the atrial skirt and the ventricular skirt therebyallowing self-expansion thereof. Further retraction of the outer sheathreleases a constraint from the tab thereby allowing a tip of the tab toradially self-expand outward forming a window between an edge of theatrial skirt and the tip of the tab. A base portion of the tab remainsconstrained by the outer sheath and actuation of the pusher element intoengagement with the base portion actuates the tip of the tab to open thewindow to its maximum size. Further retraction of the outer sheath orfurther actuation of the pusher element removes the constraint from thebase portion of the tab, thereby at least partially closing the window.

The base portion may self-expand radially outward when the constraint isreleased therefrom, and the tip of the tab may move toward the edge ofthe atrial skirt to close the window. A cover may be disposed at leastpartially over the prosthetic cardiac valve in order to facilitatetissue ingrowth. The cover may comprise fabric, tissue, or a polymer.The tab may be adapted to engage a fibrous trigone, or the tab may beadapted to engage an anterior or a posterior mitral valve leaflet.

In yet another aspect of the present invention, a method for anchoring aprosthetic valve to a cardiac valve having a valve leaflet comprisesproviding a prosthetic cardiac valve and providing a delivery system.The cardiac valve comprises an atrial skirt, a ventricular skirt, and atab coupled to the ventricular skirt. The delivery system comprises anouter sheath and a pusher element, wherein the cardiac valve is carriedby the delivery system and the pusher element is slidably disposed underthe outer sheath. The method also comprises self-expanding the atrialskirt into engagement with an atrial surface of the cardiac valve,self-expanding ventricular skirt into engagement with a ventricularsurface of the cardiac valve, and self-expanding the tab such that a tipof the tab expands radially outward to form a window between an edge ofthe atrial skirt and the tip of the tab. While a base portion of the tabremains constrained by the outer sheath, the method comprises openingthe window to its maximum size, and receiving a valve leaflet into thewindow. The window is then closed.

Self-expanding the atrial skirt may comprise retracting the outer sheathto remove a constraint therefrom. Self-expanding the ventricular skirtmay comprise retracting the outer sheath to remove a constrainttherefrom. Self-expanding the tab may comprise retracting the outersheath to remove a constraint therefrom. Opening the window may compriseactuating the pusher element into engagement with the base portionthereby moving the tip away from edge of the atrial skirt. Closing thewindow may comprise further retraction of the outer sheath to remove aconstraint from the base portion, thereby allowing the base portion toradially expand outward and the tip to move toward the edge of theatrial skirt. Closing the window may comprise disengaging the pusherelement from the base portion, thereby allowing the base portion toreturn to an unbiased position. The unbiased position may be radiallyoutward away from the delivery system. Closing the window may comprisepushing the base portion out of the outer sheath with the pusherelement, thereby allowing the base portion to expand radially outwardand the tip to move toward the edge of the atrial skirt. The valveleaflet may comprise an anterior mitral valve leaflet, and the methodmay further comprise engaging the tip of the tab with a fibrous trigoneof the mitral valve. The valve leaflet may comprise a posterior mitralvalve leaflet and the method may further comprise engaging the tab withthe posterior mitral valve leaflet.

These and other embodiments are described in further detail in thefollowing description related to the appended drawing figures.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a schematic illustration of the left ventricle of a heartshowing blood flow during systole with arrows.

FIG. 2 is a schematic illustration of the left ventricle of a hearthaving prolapsed leaflets in the mitral valve.

FIG. 3 is a schematic illustration of a heart in a patient sufferingfrom cardiomyopathy where the heart is dilated and the leaflets do notmeet.

FIG. 3A shows normal closure of the valve leaflets.

FIG. 3B shows abnormal closure of the valve leaflets.

FIG. 4 illustrates mitral valve regurgitation in the left ventricle of aheart having impaired papillary muscles.

FIGS. 5A-5B illustrate anatomy of the mitral valve.

FIG. 6 illustrates an exemplary embodiment of an uncovered frame in aprosthetic cardiac valve, with the frame flattened out and unrolled.

FIG. 7 illustrates another exemplary embodiment of an uncovered frame ina prosthetic cardiac valve, with the frame flattened out and unrolled.

FIG. 8 illustrates still another exemplary embodiment of an uncoveredframe in a prosthetic cardiac valve, with the frame flattened out andunrolled.

FIG. 9A illustrates a perspective view of an uncovered frame in aprosthetic cardiac valve after it has expanded.

FIG. 9B illustrates a top view of the embodiment in FIG. 9A.

FIG. 10 illustrates the frame of FIG. 9A with the covering therebyforming a prosthetic cardiac valve.

FIGS. 11A-11D illustrate an exemplary embodiment of a delivery systemused to transapically deliver a prosthetic cardiac valve.

FIGS. 12A-12L illustrate an exemplary method of implanting a prostheticcardiac valve.

FIGS. 13A-13L illustrate another exemplary method of implanting aprosthetic cardiac valve.

FIG. 14 illustrates engagement of the prosthetic valve tabs with thevalve leaflets.

FIGS. 15A-15B illustrate release of a prosthetic valve from a deliverysystem.

FIGS. 16A-16B illustrate release of a prosthetic valve from a deliverysystem.

FIGS. 17A-17B schematically illustrate deployment of a prosthetic valvefrom a delivery system.

FIGS. 18A-18B illustrate an embodiment of a prosthetic valve anddelivery system that controls deployment of the prosthetic valve.

FIGS. 19A-19B illustrate another embodiment of a prosthetic valve anddelivery system that controls deployment of the prosthetic valve.

FIGS. 20A-20B illustrate still another embodiment of a prosthetic valveand delivery system that controls deployment of the prosthetic valve.

DETAILED DESCRIPTION OF THE INVENTION

Specific embodiments of the disclosed device, delivery system, andmethod will now be described with reference to the drawings. Nothing inthis detailed description is intended to imply that any particularcomponent, feature, or step is essential to the invention.

Cardiac Anatomy. The left ventricle LV of a normal heart H in systole isillustrated in FIG. 1. The left ventricle LV is contracting and bloodflows outwardly through the aortic valve AV, a tricuspid valve in thedirection of the arrows. Back flow of blood or “regurgitation” throughthe mitral valve MV is prevented since the mitral valve is configured asa “check valve” which prevents back flow when pressure in the leftventricle is higher than that in the left atrium LA. The mitral valve MVcomprises a pair of leaflets having free edges FE which meet evenly toclose, as illustrated in FIG. 1. The opposite ends of the leaflets LFare attached to the surrounding heart structure along an annular regionreferred to as the annulus AN. The free edges FE of the leaflets LF aresecured to the lower portions of the left ventricle LV through chordaetendineae CT (also referred to herein as the chordae) which include aplurality of branching tendons secured over the lower surfaces of eachof the valve leaflets LF. The chordae CT in turn, are attached to thepapillary muscles PM which extend upwardly from the lower portions ofthe left ventricle and interventricular septum IVS.

Referring now to FIGS. 2-4, a number of structural defects in the heartcan cause mitral valve regurgitation. Ruptured chordae RCT, as shown inFIG. 2, can cause a valve leaflet LF2 to prolapse since inadequatetension is transmitted to the leaflet via the chordae. While the otherleaflet LF1 maintains a normal profile, the two valve leaflets do notproperly meet and leakage from the left ventricle LV into the leftatrium LA will occur, as shown by the arrow.

Regurgitation also occurs in patients suffering from cardiomyopathywhere the heart is dilated and the increased size prevents the valveleaflets LF from meeting properly, as shown in FIG. 3. The enlargementof the heart causes the mitral annulus to become enlarged, making itimpossible for the free edges FE to meet during systole. The free edgesof the anterior and posterior leaflets normally meet along a line ofcoaptation C as shown in FIG. 3A, but a significant gap G can be left inpatients suffering from cardiomyopathy, as shown in FIG. 3B.

Mitral valve regurgitation can also occur in patients who have sufferedischemic heart disease where the functioning of the papillary muscles PMis impaired, as illustrated in FIG. 4. As the left ventricle LVcontracts during systole, the papillary muscles PM do not contractsufficiently to effect proper closure. The leaflets LF1 and LF2 thenprolapse, as illustrated. Leakage again occurs from the left ventricleLV to the left atrium LA, as shown by the arrow.

FIG. 5A more clearly illustrates the anatomy of a mitral valve MV whichis a bicuspid valve having an anterior side ANT and a posterior sidePOST. The valve includes an anterior (aortic) leaflet AL and a posterior(mural) leaflet PL. Chordae tendineae CT couple the valve leaflets AL,PL with the antero-lateral papillary muscle ALPM and the postero-medialpapillary muscle PMPM. The valve leaflets AL, PL join one another alonga line referred to as the antero-lateral commissure ALC and theposterior-medial commissure PMC. The annulus AN circumscribes the valveleaflets, and two regions adjacent an anterior portion of the annulus,on opposite sides of the anterior leaflet are referred to as the leftfibrous trigone LFT and also the right fibrous trigone RFT. These areasare indicted generally by the solid triangles. FIG. 5B more clearlyillustrates the left and right fibrous trigones, LFT, RFT.

While various surgical techniques as well as implantable devices havebeen proposed and appear to be promising treatments for mitralregurgitation, surgical approaches can require a lengthy recoveryperiod, and implantable devices have varying clinical results.Therefore, there still is a need for improved devices and methods fortreating mitral regurgitation. While the embodiments disclosed hereinare directed to an implantable prosthetic mitral valve for treatingmitral regurgitation, one of skill in the art will appreciate that thisis not intended to be limiting, and the device and methods disclosedherein may also be used to treat other cardiac valves such as thetricuspid valve, aortic valve, pulmonary valve, etc, as well as othervalves in the body such as venous valves, as well as valves in thegastrointestinal system, respiratory system, and other anatomicalvalves.

Prosthetic Valve. Prosthetic valves have been surgically implanted inthe heart as a treatment for mitral regurgitation. Some of these valveshave been valves harvested from animals such as porcine valves, othermechanical valves are manufactured from rigid components, and stillothers are manufactured from pericardial tissues. More recently,minimally invasive technology has been used to deliver prosthetic valvesto the heart. These valves typically include an anchor for securing thevalve to the patient's heart, and a valve mechanism, either a rigidvalve, a valve with animal tissue, or combinations thereof.

The prosthetic valve once implanted, takes over for a malfunctioningnative valve, thereby reducing or eliminating valvar insufficiency.While some of these valves appear promising, there still is a need forimproved valves. Positioning and anchoring the prosthetic valve in thenative anatomy remains a challenge. The following discloses exemplaryembodiments of a prosthetic valve, a delivery system for the prostheticvalve, and methods of delivering the valve that overcome some of thechallenges associated with existing prosthetic valves.

FIG. 6 illustrates an exemplary embodiment of a prosthetic cardiac valvein the collapsed configuration. Coverings from the frame (e.g. fabric ortissue) has been removed to permit observation of the underlying frame600. The frame has been unrolled and flattened out. The prosthetic valveframe 600 has an atrial region 606, an annular region 608, and aventricular region 610. The frame 600 is formed from a plurality ofinterconnected struts that form a series of peaks and valleys which canexpand and contract relative to one another thereby permitting the frameto be loaded onto a delivery catheter in a collapsed configuration, andthen radially expanded at a target treatment site for implantation.Preferred embodiments are self-expanding and may be fabricated usingsuper elastic nitinol or other self-expanding materials. Shape memoryalloys that spring open above a transition temperature may also be used,and expandable members may also be used to expand the frame when plasticdeformation (e.g. balloon expansion) is required to open the frame.

Atrial region 606 has a skirt 616 which includes a plurality ofinterconnected struts that form a series of peaks and valleys. In thisregion, the struts are skew relative to one another and thus theresulting cell pattern has an enlarged end and the opposite end tapersto a smaller end. In preferred embodiments, the anterior portion of theatrial skirt does not have a flanged region like the posterior portion,thus the anterior portion 602 of the atrial region may have shorterstruts than the posterior region 604. Thus the peaks and valleys in theanterior portion are axially offset from those in the remainingposterior portion of the atrial region. This may be advantageous as itprevents the struts in the anterior portion of the atrial skirt fromprotruding upwards potentially impinging against the left atrium andcausing perforations. Additionally, the shortened struts and offsetpeaks and valleys form an alignment element 614 that can assist thephysician to visualize delivery of the prosthetic valve to the mitralvalve and alignment of the prosthetic valve prior to expansion of theprosthetic valve. Optional radiopaque markers 614 a are disposed oneither side of the offset peaks and valleys and further help withvisualization during implantation of the valve. The atrial regionpreferably self-expands to either a cylindrical shape, or it may have aD-shaped cross-section where the anterior portion 602 is substantiallyflat, and the posterior portion 604 is cylindrically shaped. This allowsthe atrial skirt to conform to the anatomy of the native mitral valve,thereby preventing obstruction of the aorta. Additionally, the atrialskirt may also be formed so that upon expansion, the skirt flaresoutward and forms a flange that can rest against a superior surface ofthe mitral valve. The flanged region is preferably along the posteriorportion of the atrial skirt, and the anterior portion of the atrialskirt remains flangeless, also helping to prevent aortic impingement.Or, the flange may extend entirely around the atrial skirt. The atrialregion is connected to the adjacent annular region 608 with connectingstruts which are preferably linear and substantially parallel to thelongitudinal axis of the frame.

The annular region 608 is also comprised of a plurality of axiallyoriented and interconnected struts that form peaks and valleys thatallow radial expansion. The struts are preferably parallel with oneanother and parallel with the longitudinal axis of the frame. Theannular region may also be self-expanding and expand into a cylindricalshape, or more preferably the annular region may expand to have aD-shaped cross-section as described above with respect to the atrialregion. Thus, the annular region may similarly have a flat anteriorportion, and a cylindrically shaped posterior portion. Upon delivery,the annular region is aligned with and expanded into engagement with themitral valve annulus. Connector struts join the annular region with theventricular region 610.

The ventricular region 610 also includes a plurality of interconnectedstruts that form peaks and valleys. Additionally, the struts in theventricular region form the leaflet commissures 613 which are coveredwith fabric, pericardial tissue, or other materials to form theprosthetic valve leaflets. Holes in the commissures allow suture to beattached thereto. Struts in the ventricular region also form aventricular skirt 628 which expands outward to engage the anterior andposterior mitral valve leaflets, and struts in the ventricular regionalso form the anterior tabs 624 and the posterior tab 630. The anteriortabs are designed to capture the anterior mitral valve leaflet betweenan inner surface of the anterior tab and outer surface of theventricular skirt. Any adjacent chordae tendineae may also be capturedtherebetween. Also, the tip of the anterior tab engages the fibroustrigone on an anterior portion of the mitral valve, one on the left andone on the right side. The posterior tab similarly captures theposterior mitral valve leaflet between an inner surface of the posteriortab and an outer surface of the ventricular skirt, along with anyadjacent chordae tendineae. This will be described in more detail below.

By controlling strut length or axial position of the anterior orposterior tabs along the frame, deployment of the tabs may becontrolled. Thus in this exemplary embodiment, because the length of thestruts in the anterior tabs and posterior tabs 624, 630 as well as theirrelative position along the frame are the same as one another, when aconstraining sheath is retracted away from the tabs, the anterior andposterior tabs will partially spring outward together. As theconstraining sheath is further retracted, the remainder of the anteriortabs will self-expand radially outward. Further retraction of theconstraining sheath then allows the remainder of the posterior tab tofinish its radial expansion, and finally the ventricular skirt willradially expand outward. While strut lengths and axial position of theposterior tab and the ventricular skirt are similar, internal strutsconnect the ventricular skirt with the commissures, and this delaysexpansion of the ventricular skirt slightly, thus the posterior tabfinishes expansion before the ventricular skirt. Using this sequence ofdeploying the prosthetic valve may allow the valve to more accurately bedelivered and also more securely anchored into position.

Suture holes 621 are disposed along the struts of the annular region aswell as the ventricular region to allow attachment of a cover such aspericardium or a polymer such as Dacron or ePTFE. The suture holes mayalso be disposed along any other part of the frame. Barbs 623 aredisposed along the ventricular skirt 628 to help anchor the prostheticvalve to adjacent tissue. Commissure tabs or tabs 612 are disposed onthe tips of the commissures 613 and may be used to releasably couple thecommissures with a delivery system as will be described below. Thisallows the frame to expand first, and then the commissures may bereleased from the delivery system afterwards. One of skill in the artwill appreciate that a number of strut geometries may be used, andadditionally that strut dimensions such as length, width, thickness,etc. may be adjusted in order to provide the anchor with the desiredmechanical properties such as stiffness, radial crush strength,commissure deflection, etc. Therefore, the illustrated geometry is notintended to be limiting.

The frame may be formed by EDM, laser cutting, photochemical etching, orother techniques known in the art. Hypodermic tubing or flat sheets maybe used to form the frame. Once the frame has been cut and formed into acylinder, it may be radially expanded into a desired geometry and heattreated using known processes to set the shape. Thus, the prostheticvalve may be loaded onto a delivery catheter in a collapsedconfiguration and constrained in the collapsed configuration with aconstraining sheath. Removal of the constraining sheath will allow theanchor to self-expand into its unbiased pre-set shape. In otherembodiments, an expandable member such as a balloon may be used toradially expand the anchor into its preferred expanded configuration.

FIG. 7 illustrates another exemplary embodiment of a prosthetic cardiacvalve in the collapsed configuration, and similar to the previousembodiment with the major difference being the strut lengths in theanterior tabs, posterior tab, and ventricular skirt. Varying the strutlengths allow the sequence of expansion of the anterior and posteriortabs and ventricular skirt to be controlled. Coverings from the frame(e.g. fabric or tissue) has been removed to permit observation of theunderlying frame 700. The frame has been unrolled and flattened out. Theprosthetic valve frame 700 has an atrial region 706, an annular region708, and a ventricular region 710. The frame 700 is formed from aplurality of interconnected struts that form a series of peaks andvalleys which can expand and contract relative to one another therebypermitting the frame to be loaded onto a delivery catheter in acollapsed configuration, and then radially expanded at a targettreatment site for implantation. Preferred embodiments areself-expanding and may be fabricated using super elastic nitinol orother self-expanding materials. Shape memory alloys that spring openabove a transition temperature may also be used, and expandable membersmay also be used to expand the frame when plastic deformation (e.g.balloon expansion) is required to open the frame.

Atrial region 706 has a skirt 716 which includes a plurality ofinterconnected struts that form a series of peaks and valleys. In thisregion, the struts are skew relative to one another and thus theresulting cell pattern has an enlarged end and the opposite end tapersto a smaller end. An anterior portion 702 of the atrial region hasshorter struts than the posterior region 704. Thus the peaks and valleysin the anterior portion are axially offset from those in the remainingposterior portion of the atrial region. This allows creation of analignment element 714 to help the physician deliver the prosthetic valveto the mitral valve and align the prosthetic valve prior to expansion ofthe prosthetic valve. Other aspects of the atrial region 706 are similarto those of the atrial region 606 in FIG. 6. Optional radiopaque markers714 a are disposed on either side of the offset peaks and valleys andhelp with visualization during implantation of the valve. The atrialregion preferably self-expands to either a cylindrical shape, or it mayhave a D-shaped cross-section where the anterior portion 702 issubstantially flat, and the posterior portion 704 is cylindricallyshaped. This allows the atrial skirt to conform to the anatomy of thenative mitral valve, thereby preventing obstruction of the leftventricular outflow tract. Additionally, the atrial skirt may also beformed so that upon expansion, the skirt flares outward and forms aflange that can rest against a superior surface of the mitral valve. Theflanged region is preferably along the posterior portion of the atrialskirt, and the anterior portion of the atrial skirt remains flangeless.Or, the flange may extend entirely around the atrial skirt. The atrialregion is connected to the adjacent annular region 708 with connectingstruts which are preferably linear and substantially parallel to thelongitudinal axis of the frame.

The annular region 708 is also comprised of a plurality of axiallyoriented and interconnected struts that form peaks and valleys thatallow radial expansion. The struts are preferably parallel with oneanother and parallel with the longitudinal axis of the frame. Theannular region may also be self-expanding and expand into a cylindricalshape, or more preferably the annular region may expand to have aD-shaped cross-section as described above with respect to the atrialregion. Thus, the annular region may similarly have a flat anteriorportion, and a cylindrically shaped posterior portion. Upon delivery,the annular region is aligned with and expanded into engagement with themitral valve annulus. Connector struts join the annular region with theventricular region 710.

The ventricular region 710 also includes a plurality of interconnectedstruts that form peaks and valleys. Additionally, the struts in theventricular region form the leaflet commissures 713 which are coveredwith fabric, pericardial tissue, or other materials to form theprosthetic valve leaflets. Holes in the commissures allow suture to beattached thereto. Struts in the ventricular region also form aventricular skirt 728 which expands outward to engage the anterior andposterior mitral valve leaflets, and struts in the ventricular regionalso form the anterior tabs 724 and the posterior tab 730. The anteriortabs are designed to capture the anterior mitral valve leaflet betweenan inner surface of the anterior tab and outer surface of theventricular skirt. Any adjacent chordae tendineae may also be capturedtherebetween. Also, the tip of the anterior tab engages the fibroustrigone on an anterior portion of the mitral valve, one on the left andone on the right side. The posterior tab similarly captures theposterior mitral valve leaflet between an inner surface of the posteriortab and an outer surface of the ventricular skirt, along with anyadjacent chordae tendineae. This will be described in more detail below.

By controlling strut length or axial position of the anterior orposterior tabs along the frame, deployment of the tabs may becontrolled. Thus in this exemplary embodiment, because the length of thestruts in the anterior tabs and posterior tabs 724, 730 as well as theirrelative position along the frame are the same as one another, when aconstraining sheath is retracted away from the tabs, the anterior andposterior tabs will partially spring outward together. As theconstraining sheath is further retracted, the remainder of the anteriortabs will self-expand radially outward because they are the shortestrelative to the struts in the ventricular skirt and the posterior tab.Further retraction of the constraining sheath then allows theventricular skirt to radially expand, and finally further retraction ofthe sheath allows the remainder of the posterior tab to finish itsradial expansion. Using this sequence of deploying the prosthetic valvemay allow the valve to more accurately be delivered and also moresecurely anchored into position.

Suture holes 721 are disposed along the struts of the annular region aswell as the ventricular region to allow attachment of a cover such aspericardium or a polymer such as Dacron or ePTFE. The suture holes mayalso be disposed along any other part of the frame. Barbs 723 aredisposed along the ventricular skirt 728 to help anchor the prostheticvalve to adjacent tissue. Commissure tabs or tabs 712 are disposed onthe tips of the commissures 713 and may be used to releasably couple thecommissures with a delivery system as will be described below. Thisallows the frame to expand first, and then the commissures may bereleased from the delivery system afterwards. One of skill in the artwill appreciate that a number of strut geometries may be used, andadditionally that strut dimensions such as length, width, thickness,etc. may be adjusted in order to provide the anchor with the desiredmechanical properties such as stiffness, radial crush strength,commissure deflection, etc. Therefore, the illustrated geometry is notintended to be limiting. The frame may be formed similarly as describedabove with respect to FIG. 6.

FIG. 8 illustrates another exemplary embodiment of a prosthetic cardiacvalve in the collapsed configuration, and is similar to the previousembodiments, with the major difference being that the posterior tab isdesigned to expand to form an elongate horizontal section which allowsengagement and anchoring of the posterior tab with the sub-annularregion between the posterior leaflet and the ventricular wall. Thus, theelongate horizontal section contacts a larger region of the sub-annularregion as compared with a posterior tab that only has a tapered tipformed from a single hinge between struts. This provides enhancedanchoring of the prosthetic valve. In this exemplary embodiment, theanterior tabs will completely self-expand first, followed by theposterior tab and then the ventricular skirt. However, in somesituations external factors such as the delivery system, anatomy, etc.may alter the sequence of expansion, and therefore this is not intendedto be limiting. Coverings from the frame (e.g. fabric or tissue) havebeen removed to permit observation of the underlying frame 800. Theframe has been unrolled and flattened out. The prosthetic valve frame800 has an atrial region 806, an annular region 808, and a ventricularregion 810. The frame 800 is formed from a plurality of interconnectedstruts that form a series of peaks and valleys which can expand andcontract relative to one another thereby permitting the frame to beloaded onto a delivery catheter in a collapsed configuration, and thenradially expanded at a target treatment site for implantation. Preferredembodiments are self-expanding and may be fabricated using super elasticnitinol or other self-expanding materials. Shape memory alloys thatspring open above a transition temperature may also be used, andexpandable members may also be used to expand the frame when plasticdeformation (e.g. balloon expansion) is required to open the frame.

Atrial region 806 has a skirt 816 which includes a plurality ofinterconnected struts that form a series of peaks and valleys. In thisregion, the struts are skew relative to one another and thus theresulting cell pattern has an enlarged end and the opposite end tapersto a smaller end. An anterior portion 802 of the atrial region hasshorter struts than the posterior region 804. Thus the peaks and valleysin the anterior portion are axially offset from those in the remainingposterior portion of the atrial region. This allows creation of analignment element 814 to help the physician deliver the prosthetic valveto the mitral valve and align the prosthetic valve prior to expansion ofthe prosthetic valve. Other aspects of the atrial region 806 are similarto those of the atrial region 606 in FIG. 6. Optional radiopaque markers814 a are disposed on either side of the offset peaks and valleys andhelp with visualization during implantation of the valve. The atrialregion preferably self-expands to either a cylindrical shape, or it mayhave a D-shaped cross-section where the anterior portion 802 issubstantially flat, and the posterior portion 804 is cylindricallyshaped. This allows the atrial skirt to conform to the anatomy of thenative mitral valve, thereby preventing obstruction of the leftventricular outflow tract. Additionally, the atrial skirt may also beformed so that upon expansion, the skirt flares outward and forms aflange that can rest against a superior surface of the mitral valve. Theflanged region is preferably along the posterior portion of the atrialskirt, and the anterior portion of the atrial skirt remains flangeless.Or, the flange may extend entirely around the atrial skirt. The atrialregion is connected to the adjacent annular region 808 with connectingstruts which are preferably linear and substantially parallel to thelongitudinal axis of the frame.

The annular region 808 is also comprised of a plurality of axiallyoriented and interconnected struts that form peaks and valleys thatallow radial expansion. The struts are preferably parallel with oneanother parallel with the longitudinal axis of the frame. The annularregion may also be self-expanding and expand into a cylindrical shape,or more preferably the annular region may expand to have a D-shapedcross-section as described above with respect to the atrial region.Thus, the annular region may similarly have a flat anterior portion, anda cylindrically shaped posterior portion. Upon delivery, the annularregion is aligned with and expanded into engagement with the mitralvalve annulus. Connector struts join the annular region with theventricular region 810.

The ventricular region 810 also includes a plurality of interconnectedstruts that form peaks and valleys. Additionally, the struts in theventricular region form the leaflet commissures 813 which are coveredwith fabric, pericardial tissue, or other materials to form theprosthetic valve leaflets. Holes in the commissures allow suture to beattached thereto. Struts in the ventricular region also form aventricular skirt 828 which expands outward to engage the anterior andposterior mitral valve leaflets, and struts in the ventricular regionalso form the anterior tabs 824 and the posterior tab 830. The anteriortabs are designed to capture the anterior mitral valve leaflet betweenan inner surface of the anterior tab and outer surface of theventricular skirt. Any adjacent chordae tendineae may also be capturedtherebetween. Also, the tip of the anterior tab engages the fibroustrigone on an anterior portion of the mitral valve, one on the left andone on the right side. The posterior tab similarly captures theposterior mitral valve leaflet between an inner surface of the posteriortab and an outer surface of the ventricular skirt, along with anyadjacent chordae tendineae. This will be described in more detail below.The posterior tab is similar to the posterior tabs described above inFIGS. 6-7, except that in this embodiment, the posterior tab comprisesfour interconnected struts as opposed to two interconnected struts.Thus, in this embodiment the plurality of interconnected struts formthree hinged regions 836 along the tab. Upon expansion of the posteriortab, the hinged regions will also expand, thereby forming an elongatehorizontal section which allows engagement and anchoring of theposterior tab with the sub-annular region between the posterior leafletand the ventricular wall. This may help position and anchor theprosthetic valve better than posterior tabs which only have a smallerfootprint or a single tapered tip for engagement with the posteriorportion of the mitral valve. The posterior leaflet in this embodiment,may be substituted with any of the other posterior tabs described inthis specification.

By controlling strut length or axial position of the anterior orposterior tabs along the frame, deployment of the tabs may becontrolled. Thus in this exemplary embodiment, because the length of thestruts in the anterior tabs and posterior tabs 824, 830 as well as theirrelative position along the frame are the same as one another, when aconstraining sheath is retracted away from the tabs, the anterior andposterior tabs will partially spring outward together. As theconstraining sheath is further retracted, the remainder of the anteriortabs will self-expand radially outward because they are the shortestrelative to the struts in the ventricular skirt and the posterior tab.Further retraction of the constraining sheath then allows the remainderof the posterior tab to finish self-expanding, followed byself-expansion of the ventricular skirt. Using this sequence ofdeploying the prosthetic valve may allow the valve to more accurately bedelivered and also more securely anchored into position.

Suture holes 821 are disposed along the struts of the annular region aswell as the ventricular region to allow attachment of a cover such aspericardium or a polymer such as Dacron or ePTFE. The suture holes mayalso be disposed along any other part of the frame. Barbs 823 aredisposed along the ventricular skirt 828 to help anchor the prostheticvalve to adjacent tissue. Commissure tabs or tabs 812 are disposed onthe tips of the commissures 813 and may be used to releasably couple thecommissures with a delivery system as will be described below. Thisallows the frame to expand first, and then the commissures may bereleased from the delivery system afterwards. One of skill in the artwill appreciate that a number of strut geometries may be used, andadditionally that strut dimensions such as length, width, thickness,etc. may be adjusted in order to provide the anchor with the desiredmechanical properties such as stiffness, radial crush strength,commissure deflection, etc. Therefore, the illustrated geometry is notintended to be limiting. The frame may be formed similarly as describedabove with respect to those previously described above.

FIG. 9A illustrates the frame 900 of a prosthetic cardiac valve after ithas expanded. Any of the frame embodiments described above may take thisform as each of the above frames have similar geometry but they expandin different order. The frame includes the atrial skirt 906 withanterior portion 914 and posterior portion 916. A flanged region isformed around the posterior portion and the anterior portion remainsflangeless. Additionally, the anterior portion is generally flat, whilethe posterior portion is cylindrically shaped, thereby forming aD-shaped cross-section which accommodates the mitral valve anatomy. FIG.9B is a top view of the embodiment in FIG. 9A and more clearlyillustrates the D-shaped cross-section.

The frame also includes the annular region 910 and ventricular skirt912. Anterior tabs 904 (only one visible in this view) is fully expandedsuch that a space exists between the inner surface of the anterior taband outer surface of the ventricular skirt. This allows the anteriorleaflet and adjacent chordae to be captured therebetween. Similarly, theposterior tab 902 is also fully deployed, with a similar space betweenthe inner surface of the posterior tab 902 and an outer surface of theventricular skirt. This allows the posterior leaflet and adjacentchordae tendineae to be captured therebetween. The commissure posts 908are also visible and are disposed in the inner channel formed by theframe. The commissure posts are used to form the prosthetic mitral valveleaflets. The overall shape of the expanded frame is D-shaped, with theanterior portion flat and the posterior portion cylindrically shaped.

FIG. 10 illustrates the expanded frame covered with a cover 1002 such aspericardial tissue or a polymer such as ePTFE or a fabric like Dacronattached to the frame, thereby forming the prosthetic cardiac valve1000. The atrial skirt may be entirely covered by a material, or inpreferred embodiments, the covering is only disposed between adjacentstruts 1012 in adjacent cells in the flanged portion of the atrialskirt. The area 1014 between adjacent struts within the same cell remainuncovered. This allows blood flow to remain substantially uninterruptedwhile the prosthetic valve is being implanted. Suture 1010 may be usedto attach the cover to the frame. In this view, only the posterior tab1006 is visible on the posterior portion of the prosthetic valve alongwith ventricular skirt 1008 and atrial skirt 1004.

Leaflet Anchoring.

The prosthetic valve is anchored to the native mitral valve using theatrial skirt, the annular region, and the ventricular skirt. Theanterior and posterior tabs further anchor the prosthetic valve to themitral valve by engaging the anterior and posterior leaflets. Becausethe valve leaflets are moving, engaging the leaflets can be challenging.In addition to the anchoring structures disclosed herein and theirsequence of deployment, other aspects of prosthetic valve deployment maybe controlled in order to successfully capture and hold the relevantanatomy of the heart during deployment of the device. Some of theseinclude a careful and meticulous design of specific geometries of theprosthetic valve frame achieved through the laser cutting process,specific geometries of the frame achieved through shape-setting of theframe, and the interaction of specific portions of the frame with adelivery system that has specialized components designed to interactwith the frame in a controllable fashion.

FIG. 14 illustrates a prosthetic valve 1408 partially deployed in amitral valve MV having an anterior leaflet AL and a posterior leafletPL. The enlarged section of the figure highlights the tabs in thepartially deployed state, and then also illustrates the tabs in thefully deployed state. The tab illustrated may be an anterior orposterior tab on the prosthetic valve. The delivery system 1402 has beentransapically delivered over a guidewire GW to span the left ventricleLV and right atrium RA. As the delivery system outer sheath 1404 isretracted, the atrial skirt 1410 deploys as described along with theannular region 1412 and the ventricular skirt 1414. The outer sheath1404 constrains a base portion of the anterior and posterior tabs 1406thereby only permitting the tabs to partially expand radially outwardafter the atrial skirt, to a horizontal position or substantiallyhorizontal position that is transverse to the longitudinal axis of theprosthesis. This creates a window 1416 between an edge of the atrialskirt 1410 and a tip of the tab 1406 which can receive the valveleaflet. Preferably, this window gap is as wide as possible in order toensure that the valve leaflet enters the window. Once the outer sheath1404 is fully retracted, the ventricular skirt 1414 fully deploys alongwith the tabs 1406. A base portion of the tab is released from theconstraint of the outer sheath, and this allows the tab to furtherexpand radially outward from its horizontal position or substantiallyhorizontal position to a more vertical position. The more verticalposition may be parallel or substantially parallel to the longitudinalaxis of the prosthesis, and may still be transverse to the longitudinalaxis of the prosthesis, but the angle therebetween is reduced relativeto when the base portion of the tab is released. Thus the tip of the tab1406 also moves closer to the edge of the atrial skirt 1410, therebyclosing the window 1416 and helping to ensure that the valve leafletwill be engaged therein. It would therefore be desirable to control thewindow size during deployment to ensure maximum gap during deployment,and minimum gap after full deployment.

FIGS. 15A-15B illustrate release of a prosthetic valve from a deliverysystem and also how the configuration of the leaflet receiving windowchanges during various stages of deployment. In FIG. 15A the outersheath 1404 of the delivery system 1402 has been partially retractedaway from the prosthetic valve such that the atrial skirt 1410 andannular region 1412 have already self-expanded. Similarly theventricular skirt 1414 has partially self-expanded along withventricular tab 1406. The ventricular tab 1406 may be an anterior tab ora posterior tab. The tip 1406 a of the ventricular tab 1406 isunconstrained and self-expands radially outward to an almost horizontalposition or a substantially horizontal position that is transverse tothe longitudinal axis of the prosthesis while the base 1406 b of theventricular tab 1406 remains constrained under the tip 1404 a of theouter sheath 1404. A commissure post 1420 couples the prosthetic valvewith the delivery catheter because one end of the commissure post 1420remains in receptacle 1422 on the delivery catheter and this isconstrained by bell catheter 1418 which is disposed over the innercatheter 1424. Thus, in FIG. 15A, window 1416 is formed between the tip1406 a of tab 1406 and the edge 1410 a of the atrial skirt 1410. The gapbetween the tip 1406 a and edge 1410 is maximum in this position inorder to allow receipt of the valve leaflet. The valve leaflet is thenreceived in a leaflet receptacle formed by the inner surface of theatrial skirt 1410, an outer surface of the annular region 1412, an outersurface of the ventricular skirt 1414, and the inner surface of theventricular tab 1406.

In FIG. 15B, the outer sheath 1404 has been further retracted therebyreleasing the base 1406 b of the ventricular tab 1406 from the outersheath 1404 constraint, allowing the ventricular skirt 1414 and theventricular tab 1406 to further self-expand radially outward. Thus thebase 1406 b self-expands outward and pivots or swings away from thedelivery system. This results in tip 1406 a of the ventricular tab 1406rotating and translating so that it moves upward and closer to the edge1410 a of the atrial skirt 1410, thereby reducing the gap and at leastpartially closing window 1416. The tab also expands radially outwardfrom its horizontal position or substantially horizontal position to amore vertical position that may be parallel or substantially parallel tothe longitudinal axis of the prosthesis, and may still be transverse tothe longitudinal axis of the prosthesis. The angle between the tab andthe ventricular skirt is therefore reduced relative to when the baseportion of the tab is released and the window preferably closes enoughto so that the valve leaflet is engaged in the leaflet receptaclethereby anchoring the prosthetic valve to the leaflet. The commissurepost 1420 remains coupled to the delivery system until the bell catheteris retracted later on as described elsewhere in this specification.While this description only describes one ventricular tab, one of skillin the art will appreciate that the same disclosure may apply to allventricular tabs in a prosthetic valve, for example the two anteriortabs and the one posterior tab described in embodiments herein.

FIGS. 16A-16B are similar to FIG. 15A but provide landmarkinginformation pertinent to the deployment of a prosthetic valve. Featureshave been relabeled for ease of discussion. The landmarks are used toaid in the description of the mechanical interactions taking placeduring the deployment of a prosthetic valve. While not being bound byany particular theory, the following variables and mechanisms ofoperation are believed to be relevant to the interaction and deploymentof the prosthetic valve and they have been labeled as follows:

-   -   A=Anchoring point of valve commissure in receptacle of delivery        system    -   B=Insertion point of commissure post into ventricular skirt    -   C=Edge of atrial skirt    -   D=Tip of ventricular tab    -   E=Insertion point of ventricular skirt strut into ventricular        tab    -   F=Leading edge of outer sheath catheter    -   G=Contact point of base of ventricular tab with bell catheter    -   Z=Normal distance between points C and D    -   β=Angle between line AB and line BE    -   α=Angle between line BE and line ED    -   φ₁=Outer diameter of outer sheath catheter    -   φ₂=Outer diameter of bell catheter

FIGS. 17A-20B schematically illustrate a prosthetic valve and deliverysystem as well as various alternative embodiments for the purpose ofexploring the interaction of various aspects of the prosthetic valvewith respective features of the delivery system. These illustrations areintended to provide a simple schematic of all relevant structures of thestent, and further detail the inherent solid mechanical deformationspresent. The illustrations visually simplify the mechanism causingrelease and deployment of the prosthetic valve, and also provide aframework for describing alternative embodiments that control deploymentthrough geometric and mechanical manipulations of the prosthetic valveand/or the delivery system.

FIG. 17A illustrates a prosthetic valve partially deployed from adelivery system. Thus, in FIG. 17A, the ventricular tab defined by EDextends horizontally or substantially horizontally as was previouslydescribed above. FIG. 17B illustrates the prosthetic valve after furtherdeployment, but not complete release from the delivery system. Theventricular tab changes position so that it is now vertically orientedand parallel or substantially parallel to the longitudinal axis of theprosthesis as previously described above. Let points C and D lie withinhorizontal, parallel planes. Let the normal distance between points Cand D be referenced as Z₁. In order to successfully receive and engage anative mitral valve leaflet during the deployment of a prosthetic valve,Z₁ is preferably maximized. The reason for this is simple. The areabounded by points C, B, E, and D can be thought of as a window,receptacle or the space in which leaflet receipt and engagement occurs,and will become the space where the native leaflet will rest afterdeployment (area bounded by C, B, E, D in FIG. 17B. Thus, the larger thewindow (Z₁), the greater the chance of catching a leaflet duringdeployment. As seen in FIG. 17B, the final post deployment configurationreveals Z₂ being substantially smaller than Z₁, illustrating thelatching or “grabbing” effect that the ventricular tabs (anterior tabs,or posterior tabs, or other tabs) have with respect to native mitralleaflets. Since a preferred embodiment would allow for the maximizationof Z₁, techniques and methods that may be used to obtain maximum windowsize are described below.

As shown in FIG. 17A and with respect to the shape-setting of theprosthetic valve, there are at least three main attributes that can bemanipulated in order to maximize Z₁. Let it be assumed that no changeswill be made to the atrial side of the prosthetic valve, which includesany geometry above the point specified by B.

For the first attribute, modifications to the branch ED can be made. Bygradually curving ED down and away from EB, point D is substantiallylowered, and the distance Z₁ becomes larger. The angle α₁ can also beincreased by shape-setting the branch ED at a larger angle from EB,starting the bend at point E and allowing ED to rotate about point E.

The second attribute is the length of branch BE. All other branchesremaining unchanged, if branch BE is made longer the tendency is to beardown on branch FED, rotating it about point F and increasing α₁.

The third attribute is the shape of the branch EG, and its interactionwith the point F. As the ventricular tab is released, the base (branchEG) is dragged along point F which represents the leading edge of theouter sheath catheter. By curving the branch EG down and away frombranch EB, the ventricular tab is both delayed in its release (a veryuseful characteristic), and made to deploy at a larger α₁. Reducing thelength of branch EG while maintaining the length of branch GD also has alevering effect, which amplifies the angular displacement betweenbranches EB and ED. In the schematic this is achieved by moving theattachment point (E) of the ventricular tab closer to point F. Thus, anyangular displacement of EG about E will be amplified, and the angulardisplacement of branch ED (α₁) will increase. In practice, this effectcan also be created by subtle manipulations to the geometry of specificportions of the delivery system, and these manipulations are describedin greater detail below.

FIGS. 18A-20B schematically illustrate various embodiments of prostheticvalves and delivery systems that have features which help to maximizewindow size Z₁. Let it again be assumed that no changes will be made tothe atrial side of the prosthetic valve, which includes any geometryabove the point specified by B. In these cases, all methods used toaffect Z₁ are brought about through interactions between the prostheticvalve and the delivery system, and not through manipulations toprosthetic valve geometry or shape-setting procedures. The atrial skirtor flange deploys first and anchors the prosthesis in the atrium andthen the rest of the prosthesis is anchored to the mitral valve annulusand ventricle. The ventricular tab deploys similarly as described above;when first partially deployed it is horizontal or substantiallyhorizontal and after the tab is released from the delivery system, thetab moves more vertically so that it is parallel or substantiallyparallel to the longitudinal axis of the prosthesis.

FIG. 18A illustrates a first embodiment utilizing the levering effectseen between branches EG and ED. By decreasing the horizontal distancebetween points G and F seen in FIG. 18B, angular displacement (α₁) isagain increased. However, in this case the change is brought about by areduction in the diameter of the outer sheath catheter 1404, whichbrings it closer to the bell catheter 1418 and thereby acts to shortenthe branch FG. In this case the fulcrum is more readily felt at thepoint F, as opposed to the point E when prosthetic valve modificationsare employed. FIG. 18B schematically illustrates this embodiment and theresulting larger window Z₁.

FIGS. 19A-19B illustrate a second embodiment for increasing window sizeZ₁. The second attribute makes use of a camming action that can beemployed on the leading edge of the sheath catheter 1404. In FIG. 19A, acammed inner surface 1902 is illustrated. This cammed inner surface 1902may be an annular inner flange or other structure that interacts withthe prescribed shape of the branch FG on the prosthetic valve, and actsas a translating cam for the purpose of precise control of a translatingfollower, embodied by the branch ED. Both the rate of angulardisplacement ({dot over (α)}₁), and angular displacement (α₁) can becontrolled by the use of a camming action in this respect. Thus, thespeed of the recoil of a ventricular tab observed during deployment canbe more precisely controlled, although it is still heavily dependent onthe spring stiffness of the material from which it is made. FIG. 19Billustrates engagement of the cam 1902 with the base of the ventriculartab during deployment which facilitates formation of wider window Z₁because the cam causes the tip of the ventricular tab to take a morehorizontal position during deployment.

FIGS. 20A-20B illustrate still another embodiment for increasing windowsize Z₁. The third attribute takes the form of a pushing mechanism suchas a pusher element 2012 that interacts with the portion of the base ofa ventricular tab between points G and F. By applying force directlyupwards on the prosthetic valve at the location of G, the rotation of EDabout point E can be influenced directly, in a controllable manner. FIG.20B illustrates the pusher element 2012 pushing against the base of theventricular tab thereby further opening the window Z₁.

Delivery System. FIGS. 11A-11D illustrate an exemplary embodiment of adelivery system that may be used to deliver any of the prostheticcardiac valves disclosed in this specification. Actuation of thedelivery system allows the prosthetic cardiac valve to be deployed asdescribed elsewhere in this specification. While the delivery system isdesigned to preferably deliver the prosthetic cardiac valvetransapically, one of skill in the art will appreciate that it may alsobe modified so that the prosthetic valve may be delivered via a cathetertransluminally, such using a transseptal route. One of skill in the artwill appreciate that using a transseptal route may require the relativemotion of the various shafts to be modified in order to accommodate theposition of the delivery system relative to the mitral valve.

FIG. 11A illustrates a perspective view of delivery system 1100. Thedelivery system 1100 includes a handle 1112 near a proximal end of thedelivery system and a distal tissue penetrating tip 1110. Four elongateshafts are included in the delivery system and include an outer sheathcatheter shaft 1102, a bell catheter shaft 1104 which is slidablydisposed in the outer sheath catheter shaft 1102, a hub catheter shaft1106 which remains stationary relative to the other shafts, but the bellcatheter shaft slides relative to the hub shaft, and finally an innerguidewire catheter shaft 1108 which is also fixed relative to the othershafts and has a lumen sized to receive a guidewire which passestherethrough and exits the distal tissue penetrating tip. An actuatormechanism 1114 is used to control movement of the various shafts as willbe explained in greater detail below, and flush lines 1116, 1118 withluer connectors are used to flush the annular regions between adjacentshafts. Flush line 1118 is used to flush the annular space between theouter sheath catheter shaft 1102 and the bell catheter shaft 1104. Flushline 1116 is used to flush the annular space between the bell catheter1104 and the hub catheter 1106. The inner guidewire catheter shaft 1108is stationary relative to the hub catheter 1106 therefore the annularspace may be sealed with an o-ring or other material. Luer connector1122 allows flushing of the guidewire lumen and a hemostatic valve suchas a Tuohy-Borst may be coupled to the luer connector to allow aguidewire to be advanced through the guidewire catheter shaft whilemaintaining hemostasis. Screws 1120 keep the handle housing coupledtogether. FIG. 11B illustrates a sideview of the delivery system 1100.

FIG. 11C is a partial exploded view of the delivery system 1100 and moreclearly illustrates the components in the handle 1112 and how theyinteract. The handle 1112 includes a housing having two halves 1112 a,1112 b which hold all the components. The handle is preferably heldtogether with screws 1120 and nuts 1120 b, although it may also besealed using other techniques such as a press fit, snap fit, adhesivebonding, ultrasonic welding, etc. Rotation of actuator wheel 1114 istranslated into linear motion of threaded insert 1124. The outer sheathcatheter shaft 1102 is coupled to the threaded insert 1124, thereforerotation of actuator wheel 1114 in one direction will advance the sheathcatheter shaft 1102, and rotation in the opposite direction will retractthe sheath catheter shaft 1102. Further rotation of actuator wheel 1114retracts threaded insert 1124 enough to bump into pins 1126 which arecoupled to insert 1128, thereby also moving insert 1128. The bellcatheter shaft 1106 is coupled to insert 1128, therefore furtherrotation of the actuator wheel 1114 will move the outer shaft 1102 andalso move the bell catheter shaft 1106. Rotation of the actuator wheelin the opposite direction advances the sheath and threaded insert 1124disengages from pins 1126. Spring 1130 returns insert 1128 to itsunbiased position, thereby returning the bell catheter shaft to itsunbiased position.

Any of the prosthetic cardiac valves disclosed herein may be carried bydelivery system 1100. The atrial skirt, annular skirt, anterior tabs,posterior tab and ventricular skirt are loaded over the bell cathetershaft and disposed under the outer sheath catheter shaft 1102. Theventricular skirt is loaded proximally so that it is closest to thehandle 1112 and the atrial skirt is loaded most distally so it isclosest to the tip 1110. Therefore, retraction of outer sheath cathetershaft 1102 plays a significant part in controlling deployment of theprosthetic cardiac valve. The atrial skirt therefore expands first whenthe outer sheath catheter is retracted. The prosthetic valve commissuresmay be coupled with a hub 1106 a on the distal portion of hub catheter1106 and then the bell catheter shaft is disposed thereover, therebyreleasably engaging the commissures with the delivery catheter. Onceother portions of the prosthetic cardiac valve have expanded, thecommissures may be released.

FIG. 11D highlights the distal portion of the delivery system 1100.Outer sheath catheter shaft 1102 advances and retracts relative to bellcatheter shaft 1104 which is slidably disposed in the outer sheathcatheter shaft 1102. Hub catheter shaft 1106 is shown slidably disposedin bell catheter shaft 1104 and with bell catheter shaft 1104 retractedso as to expose the hub 1106 a having slots 1106 b that hold theprosthetic valve commissures. Inner guidewire catheter shaft 1108 is theinnermost shaft and has a tapered conical section 1130 which provides asmooth transition for the prosthetic valve and prevents unwanted bendingor buckling of the prosthetic cardiac valve frame. Tissue penetratingtip 1110 is adapted to penetrate tissue, especially in a cardiactransapical procedure.

Delivery Method. A number of methods may be used to deliver a prostheticcardiac valve to the heart. Exemplary methods of delivering a prostheticmitral valve may include a transluminal delivery route which may also bea transseptal technique which crosses the septum between the right andleft sides of the heart, or in more preferred embodiments, a transapicalroute may be used such as illustrated in FIGS. 12A-12L. The deliverydevice previously described above may be used to deliver any of theembodiments of prosthetic valves described herein, or other deliverydevices and other prosthetic valves may also be used, such as thosedisclosed in U.S. patent application Ser. No. 13/096,572, previouslyincorporated herein by reference. However, in this preferred exemplaryembodiment, the prosthetic cardiac valve of FIG. 6 is used so that theanterior tabs deploy first, followed by the posterior tab, and then theventricular skirt.

FIG. 12A illustrates the basic anatomy of the left side of a patient'sheart including the left atrium LA and left ventricle LV. Pulmonaryveins PV return blood from the lungs to the left atrium and the blood isthen pumped from the left atrium into the left ventricle across themitral valve MV. The mitral valve includes an anterior leaflet AL on ananterior side A of the valve and a posterior leaflet PL on a posteriorside P of the valve. The leaflets are attached to chordae tendineae CTwhich are subsequently secured to the heart walls with papillary musclesPM. The blood is then pumped out of the left ventricle into the aorta Aowith the aortic valve AV preventing regurgitation.

FIG. 12B illustrates transapical delivery of a delivery system 1202through the apex of the heart into the left atrium LA. The deliverysystem 1202 may be advanced over a guidewire GW into the left atrium,and a tissue penetrating tip 1204 helps the delivery system pass throughthe apex of the heart by dilating the tissue and forming a largerchannel for the remainder of the delivery system to pass through. Thedelivery catheter carries prosthetic cardiac valve 1208. Once the distalportion of the delivery system has been advanced into the left atrium,the outer sheath 1206 may be retracted proximally (e.g. toward theoperator) thereby removing the constraint from the atrial portion of theprosthetic valve 1208. This allows the atrial skirt 1210 to self-expandradially outward first. In FIG. 12C, as the outer sheath is furtherretracted, the atrial skirt continues to self-expand and peek out, untilit fully deploys as seen in FIG. 12D. The atrial skirt may have acylindrical shape or it may be D-shaped as discussed above with a flatanterior portion and a cylindrical posterior portion so as to avoidinterfering with the aortic valve and other aspects of the leftventricular outflow tract. The prosthetic cardiac valve may be advancedupstream or downstream to properly position the atrial skirt. Inpreferred embodiments, the atrial skirt forms a flange that restsagainst a superior surface of the mitral valve and this anchors theprosthetic valve and prevents it from unwanted movement downstream intothe left ventricle. Anchoring the prosthesis in the atrium first isunexpected, since anchoring the prosthesis to the moving valve leafletsis challenging and typically would be performed first, followed byatrial anchoring which may be easier. However, atrial anchoring firstcan help seat the prosthesis more securely. Of course, one of skill inthe art recognizes that the prosthesis may be deployed in any desiredorder based on the delivery system used, as well as the design of theprosthesis itself. Thus the current prosthetic valve may anchor itselfdifferently than previous prosthetic valves. Previous prosthetic valvesmay be anchored passively in that they may be delivered by unsheathingfrom a delivery system and then pulled into place behind the leafletsfollowed by atrial anchoring. For this reason the leaflet anchors needto be deployed first, followed by the atrial anchors which are easier todeploy due to the relatively flat atrial floor. In the presentembodiment, active anchoring is utilized because the anchors changeposition and orientation during the deployment sequence to capture theventricular structures, and thereby permit the use of a reverseanchoring sequence from previous prosthetic valves.

As the outer sheath 1206 continues to be proximally retracted, theannular region of the prosthetic cardiac valve self-expands next intoengagement with the valve annulus. The annular region also preferablyhas the D-shaped geometry, although it may also be cylindrical or haveother geometries to match the native anatomy. In FIG. 12E, retraction ofsheath 1206 eventually allows both the anterior 1212 and posterior 1214tabs to partially self-expand outward preferably without engaging theanterior or posterior leaflets or the chordae tendineae. The tabsinitially expand outwardly into a horizontal or substantially horizontalposition that is transverse to the longitudinal axis of the prosthesis.In this embodiment, further retraction of the outer sheath 1206 thenallows both the anterior tabs 1212 (only one visible in this view) tocomplete their self-expansion so that the anterior leaflet is capturedbetween an inner surface of each of the anterior tabs and an outersurface of the ventricular skirt 1216, as illustrated in FIG. 12F. Theanterior tabs expand into a more vertical position that is parallel toor substantially parallel to the longitudinal axis of the prosthesis.The tabs may still be transverse to the longitudinal axis of theprosthesis. The posterior tab 1214 remains partially open, but has notcompleted its expansion yet. Additionally, the tips of the anterior tabsalso anchor into the left and right fibrous trigones of the mitralvalve, as will be illustrated in greater detail below.

In FIG. 12G, further retraction of the outer sheath 1206 then releasesthe constraints from the posterior tab 1214 allowing it to complete itsself-expansion, thereby capturing the posterior leaflet PL between aninner surface of the posterior tab 1214 and an outer surface of theventricular skirt 1218. Thus the posterior tab moves from the horizontalposition or substantially horizontal position to a more verticalposition that is parallel or substantially parallel to the longitudinalaxis of the prosthesis. In FIG. 12H, the sheath is retracted furtherreleasing the ventricular skirt 1220 and allowing the ventricular skirt1220 to radially expand outward, further capturing the anterior andposterior leaflets between the outer surface of the ventricular skirtand their respective anterior or posterior tabs. Expansion of theventricular skirt also pushes the anterior and posterior leafletsoutward, thereby ensuring that the native leaflets do not interfere withany portion of the prosthetic valve or the prosthetic valve leaflets.The prosthetic valve is now anchored in position above the mitral valve,along the annulus, to the valve leaflets, and below the mitral valve,thereby securing it in position.

Further actuation of the delivery device now retracts the outer sheath1206 and the bell catheter shaft 1222 so as to remove the constraintfrom the hub catheter 1224, as illustrated in FIG. 12I. This permits theprosthetic valve commissures 1226 to be released from the hub catheter,thus the commissures expand to their biased configuration. The deliverysystem 1202 and guidewire GW are then removed, leaving the prostheticvalve 1208 in position where it takes over for the native mitral valve,as seen in FIG. 12J.

FIGS. 12K and 12L highlight engagement of the anterior and posteriortabs with the respective anterior and posterior leaflets. In FIG. 12K,after anterior tabs 1212 have been fully expanded, they capture theanterior leaflet AL and adjacent chordae tendineae between an insidesurface of the anterior tab and an outer surface of the ventricularskirt 1220. Moreover, the tips 1228 of the anterior tabs 1212 areengaged with the fibrous trigones FT of the anterior side of the mitralvalve. The fibrous trigones are fibrous regions of the valve thus theanterior tabs further anchor the prosthetic valve into the native mitralvalve anatomy. One anterior tab anchors into the left fibrous trigone,and the other anterior tabs anchors into the right fibrous trigone. Thetrigones are on opposite sides of the anterior side of the leaflet. FIG.12L illustrates engagement of the posterior tab 1214 with the posteriorleaflet PL which is captured between an inner surface of the posteriortab and an outer surface of the ventricular skirt 1220. Additionally,adjacent chordae tendineae are also captured between the posterior taband ventricular skirt.

FIGS. 13A-13L illustrate another exemplary embodiment of a deliverymethod. This embodiment is similar to that previously described, withthe major difference being the order in which the prosthetic cardiacvalve self-expands into engagement with the mitral valve. Any deliverydevice or any prosthetic cardiac valve disclosed herein may be used,however in preferred embodiments, the embodiment of FIG. 7 is used.Varying the order may allow better positioning of the implant, easiercapturing of the valve leaflets, and better anchoring of the implant.This exemplary method also preferably uses a transapical route, althoughtransseptal may also be used.

FIG. 13A illustrates the basic anatomy of the left side of a patient'sheart including the left atrium LA and left ventricle LV. Pulmonaryveins PV return blood from the lungs to the left atrium and the blood isthen pumped from the left atrium into the left ventricle across themitral valve MV. The mitral valve includes an anterior leaflet AL on ananterior side A of the valve and a posterior leaflet PL on a posteriorside P of the valve. The leaflets are attached to chordae tendineae CTwhich are subsequently secured to the heart walls with papillary musclesPM. The blood is then pumped out of the left ventricle into the aorta AOwith the aortic valve AV preventing regurgitation of blood from theaorta back into the left ventricle.

FIG. 13B illustrates transapical delivery of a delivery system 1302through the apex of the heart into the left atrium LA. The deliverysystem 1302 may be advanced over a guidewire GW into the left atrium,and a tissue penetrating tip 1304 helps the delivery system pass throughthe apex of the heart by dilating the tissue and forming a largerchannel for the remainder of the delivery system to pass through. Thedelivery catheter carries prosthetic cardiac valve 1308. Once the distalportion of the delivery system has been advanced into the left atrium,the outer sheath 1306 may be retracted proximally (e.g. toward theoperator) thereby removing the constraint from the atrial portion of theprosthetic valve 1308. This allows the atrial skirt 1310 to self-expandradially outward. In FIG. 13C, as the outer sheath is further retracted,the atrial skirt continues to self-expand and peek out, until it fullydeploys as seen in FIG. 13D. The atrial skirt may have a cylindricalshape or it may be D-shaped as discussed above with a flat anteriorportion and a cylindrical posterior portion so as to avoid interferingwith the aortic valve and other aspects of the left ventricular outflowtract. The prosthetic cardiac valve may be advanced upstream ordownstream to properly position the atrial skirt. In preferredembodiments, the atrial skirt forms a flange that rests against asuperior surface of the mitral valve and this anchors the prostheticvalve and prevents it from unwanted movement downstream into the leftventricle. Thus, as previously described, anchoring the prosthesis tothe atrium first is unexpected and facilitates anchoring of theprosthesis.

As the outer sheath 1306 continues to be proximally retracted, theannular region of the prosthetic cardiac valve self-expands next intoengagement with the valve annulus. The annular region also preferablyhas the D-shaped geometry, although it may also be cylindrical or haveother geometries to match the native anatomy. In FIG. 13E, retraction ofsheath 1306 eventually allows both the anterior 1312 and posterior 1314tabs to partially self-expand outward preferably without engaging theanterior or posterior leaflets or the chordae tendineae. The tabs havesimilar horizontal or substantially horizontal positions as previouslydescribed in the previous embodiment. In this embodiment, furtherretraction of the outer sheath 1306 then allows both the anterior tabs1312 (only one visible in this view) to complete their self-expansion sothat the anterior leaflet is captured between an inner surface of eachof the anterior tabs and an outer surface of the ventricular skirt 1316,as illustrated in FIG. 13F. Thus, the tabs will have a more verticalposition that is parallel or substantially parallel to the prosthesis aspreviously described. The posterior tab 1214 remains partially open andhas a position generally the same as previously described, but has notcompleted its expansion yet. Additionally, the tips of the anterior tabsalso anchor into the left and right fibrous trigones of the mitralvalve, as will be illustrated in greater detail below.

In FIG. 13G, further retraction of the outer sheath 1306 then releasesthe constraint from the ventricular skirt 1320 allowing the ventricularskirt to radially expand. This then further captures the anteriorleaflets AL between the anterior tab 1312 and the ventricular skirt1316. Expansion of the ventricular skirt also pushes the anterior andposterior leaflets outward, thereby ensuring that the native leaflets donot interfere with any portion of the prosthetic valve or the prostheticvalve leaflets. Further retraction of sheath 1306 as illustrated in FIG.13H releases the constraint from the posterior tab 1314 allowing it tocomplete its self-expansion, thereby capturing the posterior leaflet PLbetween an inner surface of the posterior tab 1314 and an outer surfaceof the ventricular skirt 1318. The posterior tab then takes a morevertical position similar to that previously described above. Theprosthetic valve is now anchored in position above the mitral valve,along the annulus, to the valve leaflets, and below the mitral valve,thereby securing it in position.

Further actuation of the delivery device now retracts the outer sheath1306 and the bell catheter shaft 1322 so as to remove the constraintfrom the hub catheter 1324, as illustrated in FIG. 13I. This permits theprosthetic valve commissures 1326 to be released from the hub catheter,thus the commissures expand to their biased configuration. The deliverysystem 1302 and guidewire GW are then removed, leaving the prostheticvalve 1308 in position where it takes over for the native mitral valve,as seen in FIG. 13J.

FIGS. 13K and 13L highlight engagement of the anterior and posteriortabs with the respective anterior and posterior leaflet. In FIG. 13K,after anterior tabs 1312 have been fully expanded, they capture theanterior leaflet AL and adjacent chordae tendineae between an insidesurface of the anterior tab and an outer surface of the ventricularskirt 1320. Moreover, the tips 1328 of the anterior tabs 1312 areengaged with the fibrous trigones FT of the anterior side of the mitralvalve. The fibrous trigones are fibrous regions of the valve thus theanterior tabs further anchor the prosthetic valve into the native mitralvalve anatomy. One anterior tab anchors into the left fibrous trigone,and the other anterior tab anchors into the right fibrous trigone. Thetrigones are on opposite sides of the anterior side of the leaflet. FIG.13L illustrates engagement of the posterior tab 1314 with the posteriorleaflet PL which is captured between an inner surface of the posteriortab and an outer surface of the ventricular skirt 1320. Additionally,adjacent chordae tendineae are also captured between the posterior taband ventricular skirt.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A prosthetic valve comprising: a self-expandingframe having a superior end, an inferior end, and a midsectiontherebetween, wherein the frame has an expanded configuration and acollapsed configuration, the collapsed configuration adapted to bedelivered to a patient's heart, and the expanded configuration adaptedto anchor the self-expanding frame in the patient's heart, wherein theframe comprises: a self-expanding atrial skirt adjacent the superiorend, wherein the atrial skirt forms a flanged region afterself-expansion thereof, the flanged region configured to anchor theself-expanding frame to an atrial surface of the heart, and wherein theflanged region comprises an edge of a flange; a self-expandingventricular skirt adjacent the inferior end, wherein the ventricularskirt anchors the self-expanding frame to a ventricular surface of theheart after self-expansion thereof; and a first self-expanding tabadjacent the inferior end and coupled with the ventricular skirt, thefirst self-expanding tab having a tip, wherein the first tab radiallyself-expands when a constraint is removed therefrom, and wherein areceptacle is formed by an area bounded by an outer surface of theatrial skirt, an outer surface of the ventricular skirt, and an innersurface of the first tab, and wherein a window is defined by a gapbetween the edge of the flange and the tip of the first tab, and whereinthe gap is maximized when the tip of the first tab is unconstrained suchthat the tab expands radially outward to a position that is transverseto a longitudinal axis of the self-expanding frame and while a base ofthe first tab is at least partially constrained, and wherein the gap isminimized when the tip of the first tab is unconstrained such that thetip moves back radially inward from the transverse position when thebase of the first tab is also unconstrained, and wherein the base of thefirst tab expands radially outward when the base is unconstrained. 2.The prosthetic valve of claim 1, wherein when the gap is maximized, thewindow is adapted to receive a valve leaflet in the receptacle.
 3. Theprosthetic valve of claim 1, wherein when the gap is minimized, thereceptacle is adapted to engage the valve leaflet and anchor theprosthetic valve thereto.
 4. The prosthetic valve of claim 1, whereinthe tip of the first tab moves toward the edge of the flange when thebase of the first tab is released from a constraint.
 5. The prostheticvalve of claim 1, wherein angle α is defined by an inner surface of thefirst tab and an outer surface of the ventricular skirt, and wherein αdecreases when the base of the first tab is released from a constraintand the tip of the first tab is unconstrained.
 6. The prosthetic valveof claim 1, wherein angle α is defined by an inner surface of the firsttab and an outer surface of the ventricular skirt, and wherein α ismaximized when the tip of the first tab is unconstrained and the base ofthe first tab is at least partially constrained.
 7. The prosthesis ofclaim 1, further comprising a commissure post coupled with theself-expanding frame and having an end extending radially inward, andwherein an angle β is defined by an outer surface of the commissure postand an inner surface of the ventricular skirt, and wherein β isminimized when the base of the first tab is at least partiallyconstrained and the tip of the first tab is unconstrained.
 8. Theprosthesis of claim 1, further comprising a commissure post coupled withthe self-expanding frame and having an end extending radially inward,and wherein an angle β is defined by an outer surface of the commissurepost and an inner surface of the ventricular skirt, and wherein β ismaximized when the base of the first tab is unconstrained and the tip ofthe first tab is unconstrained.
 9. The prosthesis of claim 1, furthercomprising a commissure post coupled with the self-expanding frame andhaving an end extending radially inward, wherein the commissure post isadapted to remain coupled to a delivery catheter after the base of thefirst tab and the tip of the first tab are unconstrained.
 10. Theprosthesis of claim 1, further comprising a cover disposed at leastpartially over the self-expanding frame, the cover facilitating tissueingrowth.
 11. The prosthesis of claim 10, wherein the cover comprisesfabric, tissue or a polymer.
 12. The prosthesis of claim 1, wherein thetip of the tab is adapted to engage a fibrous trigone.
 13. Theprosthesis of claim 1, wherein the tab is adapted to engage an anterioror a posterior mitral valve leaflet.
 14. The prosthesis of claim 1,wherein the atrial skirt expands before the first tab.
 15. Theprosthesis of claim 1, wherein the atrial skirt anchors the prosthesisto the atrium before the first tab anchors the prosthesis to the valveleaflet.
 16. The prosthesis of claim 1, wherein the first tab expands toa position transverse to a longitudinal axis of the prosthesis followedby expansion to a position substantially parallel to the longitudinalaxis of the prosthesis.
 17. The prosthetic valve of claim 1, wherein thefirst tab is formed from a plurality of interconnected struts.
 18. Theprosthetic valve of claim 17, wherein the tip of the first tab is formedfrom a hinge between interconnected struts.
 19. The prosthetic valve ofclaim 1, wherein the ventricular skirt is coupled to the first tab at aninsertion point between the tip and a bottom end of the base; whereinthe base comprises a branch of interconnected struts extending from theinsertion point to a contact point at the bottom end of the base therebyallowing the base to pivot about the insertion point; wherein when thegap is maximized, the base of the first tab contacts a delivery systemat the contact point; and wherein the branch of the base expandsradially outward and pivots about the insertion point to swing away fromthe delivery system such that the contact point is no longer in contactwith the delivery system when the gap is minimized.
 20. The prostheticvalve of claim 1, wherein the ventricular skirt is coupled to the firsttab to form a Y-shaped structure having two upper members and one lowermember extending down from where the two upper members intersect,wherein one of the upper members comprises the ventricular skirt and theother of the upper members comprises an upper portion of the first tabcomprising the tip, and wherein the lower member comprises the base ofthe first tab.
 21. The prosthetic valve of claim 1, wherein uponexpansion of the frame to its expanded configuration: the atrial skirthas a D-shaped cross-section, an anterior portion of the atrial skirt issubstantially flat, a posterior portion of the atrial skirt iscylindrically shaped, and wherein the flanged region is formed by theatrial skirt along the posterior portion while the anterior portionremains flangeless.